SIST EN 1794-1:2011
(Main)Road traffic noise reducing devices - Non-acoustic performance - Part 1: Mechanical performance and stability requirements
Road traffic noise reducing devices - Non-acoustic performance - Part 1: Mechanical performance and stability requirements
This European Standard provides criteria to categorise road traffic noise reducing devices according to basic mechanical performance under standard conditions of exposure, irrespective of the materials used. A range of conditions and optional requirements is provided to allow for the wide diversity of practice within Europe. Individual aspects of performance are covered separately in the annexes. Safety considerations in the event of damage to noise reducing devices are covered in Part 2 of this European Standard.
Lärmschutzeinrichtungen an Straßen - Nichtakustische Eigenschaften - Teil 1: Mechanische Eigenschaften und Anforderungen an die Standsicherheit
Diese Europäische Norm legt Kriterien für die Klassifizierung von Lärmschutzeinrichtungen an Straßen nach grundlegenden mechanischen Eigenschaften unter Normbeanspruchungsbedingungen fest, unabhängig von den verwendeten Baustoffen. Die Norm enthält eine Reihe von Bedingungen und freigestellten Anforderungen, die die große Vielfalt der Baupraxis in Europa berücksichtigt. Einzelne Beanspruchungsarten werden in den Anhängen behandelt. Sicherheitstechnische Überlegungen im Falle der Beschädigung von Lärmschutzeinrichtungen werden in Teil 2 dieser Europäischen Norm behandelt.
Dispositifs de réduction du bruit du trafic routier - Performances non acoustiques - Partie 1: Performances mécaniques et exigences en matière de stabilité
La présente Norme européenne spécifie des critères permettant de classer les dispositifs de réduction du
bruit du trafic routier en fonction de leur performance mécanique de base dans des conditions normales
d'exposition, indépendamment des matériaux utilisés. Une gamme de conditions et d'exigences optionnelles
est donnée afin de tenir compte de la grande diversité des pratiques en Europe. Les aspects individuels des
performances sont couverts séparément dans les annexes. Les considérations relatives à la sécurité dans le
cas de dommages aux dispositifs de réduction du bruit sont également couvertes dans la partie 2 de la
présente Norme européenne.
Protihrupne ovire za cestni promet - Neakustične lastnosti - 1. del: Mehanske lastnosti in zahteve za stabilnost
Ta evropski standard podaja merila za kategorije protihrupnih ovir za cestni promet glede na osnovno mehansko zmogljivost pod standardnimi pogoji izpostavljenosti, neodvisno od uporabljenih materialov. Razpon pogojev in izbornih zahtev je na voljo, da omogoči široko raznolikost praks v Evropi. Posamični vidiki zmogljivosti so zajeti ločeno v dodatku. Varnostni vidiki v primeru poškodbe protihrupne ovire za cestni promet so zajeti v drugem delu tega evropskega standarda.
General Information
Relations
Standards Content (Sample)
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Lärmschutzeinrichtungen an Straßen - Nichtakustische Eigenschaften - Teil 1: Mechanische Eigenschaften und Anforderungen an die StandsicherheitDispositifs de réduction du bruit du trafic routier - Performances non acoustiques - Partie 1: Performances mécaniques et exigences en matière de stabilitéRoad traffic noise reducing devices - Non-acoustic performance - Part 1: Mechanical performance and stability requirements93.080.30Cestna oprema in pomožne napraveRoad equipment and installations17.140.30Emisija hrupa transportnih sredstevNoise emitted by means of transportICS:Ta slovenski standard je istoveten z:EN 1794-1:2011SIST EN 1794-1:2011en,fr,de01-julij-2011SIST EN 1794-1:2011SLOVENSKI
STANDARDSIST EN 1794-1:20041DGRPHãþD
SIST EN 1794-1:2011
EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM
EN 1794-1
January 2011 ICS 93.080.30 Supersedes EN 1794-1:2003English Version
Road traffic noise reducing devices - Non-acoustic performance - Part 1: Mechanical performance and stability requirements
Dispositifs de réduction du bruit du trafic routier - Performances non acoustiques - Partie 1: Performances mécaniques et exigences en matière de stabilité
Lärmschutzeinrichtungen an Straßen - Nichtakustische Eigenschaften - Teil 1: Mechanische Eigenschaften und Anforderungen an die Standsicherheit This European Standard was approved by CEN on 10 December 2010.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management Centre has the same status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre:
Avenue Marnix 17,
B-1000 Brussels © 2011 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 1794-1:2011: ESIST EN 1794-1:2011
EN 1794-1:2011 (E) 2 Contents page Foreword . 3Introduction . 41Scope . 52Normative references . 53Terms and definitions . 54Symbols and abbreviations . 65Requirements . 75.1General . 75.2Wind load and static load . 75.3Vibration and fatigue effects . 75.4Self weight . 75.5Impact of stones . 75.6Safety in collision . 75.7Dynamic forces from snow clearance . 76Test report . 8Annex A (normative)
Wind load and static load . 9Annex B (normative)
Self weight . 16Annex C (normative)
Impact of stones . 19Annex D (normative)
Safety in collision . 22Annex E (normative)
Dynamic load from snow clearance . 23Bibliography . 26
SIST EN 1794-1:2011
EN 1794-1:2011 (E) 3 Foreword This document (EN 1794-1:2011) has been prepared by Technical Committee CEN /TC 226 "Road equipment", the secretariat of which is held by AFNOR. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by July 2011, and conflicting national standards shall be withdrawn at the latest by July 2011. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights. This document supersedes EN 1794-1:2003. This European Standard consists of the following parts under the general title "Road traffic noise reducing devices — Non acoustic performance". Part 1: Mechanical performance and stability requirements Part 2: General safety and environmental requirements The main changes compared to the previous edition are: a) fatigue (A.2.3.2); b) the wind load for low barriers; c) addition to Annex A of a note on shape factors. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
SIST EN 1794-1:2011
EN 1794-1:2011 (E) 4 Introduction While performing their primary function, road traffic noise reducing devices are exposed to a range of forces due to wind, dynamic air pressure caused by passing traffic, and the self weight of its component parts.
They can also be subjected to shocks caused by stones or other debris thrown up by vehicle tyres and, in some countries, the dynamic force of snow ejected by equipment used to clear roads in winter. The deflections of a noise reducing device under such loads during its design life should not reduce its effectiveness. SIST EN 1794-1:2011
EN 1794-1:2011 (E) 5 1 Scope This European Standard specifies criteria to categorise road traffic noise reducing devices according to basic mechanical performance under standard conditions of exposure, irrespective of the materials used.
A range of conditions and optional requirements is provided in order to take into account the wide diversity of practice in Europe. Individual aspects of performance are covered separately in the annexes.
Safety considerations in the event of damage to noise reducing devices are covered in Part 2 of this European Standard. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. EN 1991-1-4, Eurocode 1: Actions on structures — Part 1-4: General actions — Wind actions EN 1317-1, Road restraint systems — Part 1: Terminology and general criteria for test methods EN 1317-2, Road restraint systems — Part 2: Performance classes, impact test acceptance criteria and test methods for safety barriers including vehicle parapets EN 1794-2:2011, Road traffic noise reducing devices — Non-acoustic performance — Part 2: General safety and environmental requirements 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 noise barrier noise reducing device which obstructs the direct transmission of airborne sound emanating from road traffic 3.2 cladding noise reducing device which is attached to a wall or other structure to reduce the amount of sound reflected 3.3 cover noise reducing device which either spans or overhangs the highway 3.4 structural element element whose primary function is to support or hold in place acoustic elements 3.5 acoustic element element whose primary function is to provide the acoustic performance of the device 3.6 mechanical test hammer device of the type used for measuring the elasticity of hard surfaces 3.7 test area central area of a full size panel enclosed by a margin of 125 mm from each edge, as shown in Figure C.2 SIST EN 1794-1:2011
EN 1794-1:2011 (E) 6 3.8 vehicle occupants safe device traffic safe noise reducing device for which a vehicle impact does not cause more danger to the occupants than allowed for safety barriers in EN 1317-2 NOTE However, it does not need to prevent the vehicle from going through it, nor is it presumed that parts of the device are prevented from becoming detached. 3.9 combined safety and noise barrier traffic safe noise reducing device which fulfils all the requirements for safety barriers in a given containment class as defined in EN 1317-2 3.10 wind load wind load that include all factors in this European Standard 3.11 design wind load wind load specific to a geographical region as defined in Eurocodes (EN 1991-2-4) 3.12 dynamic load load due to snow thrown against a noise reducing device by snow ploughing equipment 3.13 ploughing speed speed of the snow ploughing equipment as it passes the noise barrier 4 Symbols and abbreviations Ce(z) exposure coefficient Cp pressure coefficient d deflection, in millimetres dhmax horizontal maximum deflection, in millimetres dvmax vertical maximum deflection, in millimetres Hnrd total height of acoustic elements constituting the whole reducing device, in millimetres hae height of a single acoustic element, in millimetres L length of elements, in millimetres LS greatest length of structural element, in millimetres LA greatest free length of acoustic element (between its supporting structural elements), in millimetres q(v) dynamic pressure due to passing vehicles, in Pascals S load factor SG load factor (weight) SW load factor (wind) SIST EN 1794-1:2011
EN 1794-1:2011 (E) 7 Vref mean wind velocity at height z, in metres per second W wind pressure, in Pascals z height above the ground, in metres ρ
air density, in kilograms per cubic metre 5 Requirements 5.1 General Under any of the following loads, elements shall not become detached from their supports or fixings. 5.2 Wind load and static load Limiting values for elastic and permanent deflections shall not exceed the values specified in Annex A. To ensure connections do not fail load factors shall be applied in accordance with Annex A. NOTE This European Standard permits specifying authorities to indicate that there is no requirement for resistance to wind or static load. 5.3 Vibration and fatigue effects All the relevant standards are specified in A.2.3.2. NOTE This European Standard permits specifying authorities to indicate that there is no requirement for vibration and fatigue effect. 5.4 Self weight Under standard conditions the deflections shall not exceed the limiting values given in Annex B. 5.5 Impact of stones Damage caused by controlled impacts shall not exceed the criteria specified in Annex C. NOTE This European Standard permits specifying authorities to indicate that there is no requirement for resistance to the impact of stones. 5.6 Safety in collision When safety in collision has to be assessed, the behaviour under impacts specified in EN 1317-2 shall be classified in accordance with Annex D. NOTE This European Standard permits specifying authorities to indicate that there is no requirement for verification of safety in the event of an impact by an errant vehicle. 5.7 Dynamic forces from snow clearance When the effects of dynamic forces from snow clearance have to be assessed, this shall be done in accordance with Annex E. NOTE This European Standard permits specifying authorities to indicate that there is no requirement for resistance to the force of snow thrown sideways by clearance equipment. SIST EN 1794-1:2011
EN 1794-1:2011 (E) 8 6 Test report 6.1 Every test report on aspects of performance shall include the following information: a) number and year of this European Standard, i.e. EN 1794-1:2011; b) full description of the element or system tested, including manufacturer(s), part numbers, place and date of origin; c) description of the method of sampling, if parts of manufactured elements are evaluated by testing; d) place and date of the assessment, and the name of the assessor; e) sufficient description of any tests carried out, any results measured and the conclusions drawn about the product together with any illustrations or photographs, all as specified in the appropriate annex. 6.2 A summary report shall be produced, identifying the aspects of performance for which detailed reports are available and the level of performance assessed, where appropriate. SIST EN 1794-1:2011
EN 1794-1:2011 (E) 9 Annex A (normative)
Wind load and static load A.1 General The methods for calculating wind load on noise reducing devices have been harmonized to allow for the particular climatic conditions within each region. As considerable differences existed in the methods of calculation used in different European countries, an effort has been made to define an acceptable level of performance by applying load factors to the basic load calculated to take account of its location. Limits are placed on deflections to avoid acoustic leakage either while the noise reducing device is being subjected to its design wind load or afterwards. Adequacy of mechanical performance in fulfilling the structural criteria given in this annex is in general demonstrated by calculations taking into account the values of elastic limit, modulus of elasticity, and other factors relating to the materials employed in the construction. In cases where calculations are thought to be unreliable, tests are used to determine the resistance of the elements in the same arrangement as in the intended use of the noise reducing device. The range of temperature over which performance is within acceptance criteria is determined to enable noise reducing devices to be appropriately specified for extreme conditions of heat or cold. This annex specifies the mechanical requirements for noise reducing devices exposed to aerodynamic load, excepting the design of foundations. The method of calculating aerodynamic and static loads and the minimum mechanical requirements for structural and acoustical elements and fixing devices are given. Two sources of aerodynamic load are considered: firstly, wind forces and secondly, dynamic air pressure due to passing vehicles. The forces acting on noise absorbing cladding attached to supporting walls are also considered. A.2 Aerodynamic load A.2.1 General Aerodynamic load shall be considered acting normal to the exposed surface of the noise reducing device. NOTE Wind load and dynamic pressure due to vehicles can be assumed not to act simultaneously. A.2.2 Design wind load The design wind load shall be calculated in accordance with EN 1991-1-4, which is based on national maps showing basic wind speeds. NOTE The calculations can also be carried out taking a basic wind speed from more precise data, using a return period of 50 years. A.2.3 Dynamic effects due to vehicles A.2.3.1 Dynamic pressure For the standard cases a) to c), the following values of dynamic pressure (or suction) in Pascals, shall be used: a) traffic of vehicles in open air at a distance of 1 m from the noise reducing device and at a maximum speed of 100 km/h; SIST EN 1794-1:2011
EN 1794-1:2011 (E) 10 q(v) = 650
b) traffic of vehicles in open air at a distance of 3 m from the noise reducing device and at speeds higher than 120 km/h; q(v) = 800
c) bi-directional traffic in a tunnel, at a distance of 1 m from the noise reducing device and maximum speed of 120 km/h; q(v) = 1 500
d) in other cases, independent calculations shall be made to ascertain the magnitude of dynamic pressure. A.2.3.2 Fatigue If noise reducing devices are located close to either the side of roads or the ceiling of tunnels and covers, the combination of the following factors could lead to cycles of pressure differences and fatigue to occur: (i) shape and speed of passing vehicles; (ii) distance to and shape of the device. The relevant standards are: • EN 1991-1-4:2005, Eurocode 1: Action on structures — Part 4 General actions — Wind actions. Prescriptions are described in 7.4.1 wind loads for free standing walls and the number of loads for dynamic response is described in B.3. • EN 1993-1-9:2005, Eurocode 3: Design of steel structures — Part 1-9: Fatigue. This code give all relevant information required for steel structures. The choice is described in EN 1993-1-9:2005, Table 3.1. Alongside roads “safe live” is required. • EN 1999-1-1:2007, Eurocode 9: Design of aluminium structures — Part 1-1: General structural rules • EN 1999-1-3:2007, Eurocode 9: Design of aluminium structures — Part 1-3: Structures susceptible to fatigue A.3 Mechanical requirements for free standing noise barriers A.3.1 General The temperature range, within limits of - 30 °C to + 70 °C, over which the requirements in A.3.2 to A.3.4 are met shall be reported. For the purposes of calculation or test, temperature intervals of 10 °C shall be used. A.3.2 Structural elements A.3.2.1 General In determining deflections of structural elements, rotation and displacements originating from foundations shall not be taken into account. A.3.2.2 Vertical noise barriers a) The maximum horizontal elastic deflection dhmax, in millimetres, under the design wind load shall be less than; SIST EN 1794-1:2011
EN 1794-1:2011 (E) 11
100maxShLd= for
Hnrd ≤ 3 m
dhmax = 30 mm for 3 m ≤ Hnrd ≥ 4,5 m
150maxShLd= for Hnrd
> 4,5 m
b) when a load factor of SW = 1,5 is applied to the design wind load; i) the element shall not show any symptoms of failure such as buckling, permanent displacement of acoustic elements, or cracks greater than acceptable for exposure to a severe corrosive environment; ii) the element shall not become detached from its supports or fixings; iii) the permanent deformation dhmax, in millimetres, after release of the load shall be less than; 500maxShLd=
A.3.2.3 Non-vertical noise barriers Load due to snow, self weight, etc. shall be considered as acting together with wind load. The acceptance criteria are as given in A.3.2.2. except that additionally the elastic vertical deflection dvmax, in millimetres, shall be less than: 300maxShLd= A.3.3 Acoustic elements A.3.3.1 General An acoustic element shall not transmit loads from other acoustic elements to the structural elements unless this transmission is taken into account in the calculations. A.3.3.2 Vertical noise reducing devices a) The maximum horizontal elastic deflection, dhmax, in millimetres, due to bending under the design wind load shall be less than:
dhmax = min (40AL, 50 mm) for LA ≤ 5 m
dhmax = 100ALfor LA > 5 m b) when a load factor of S = 1,5 is applied to the design wind load; i) the element shall not show any symptoms of failure such as buckling, permanent displacement of absorptive material, or cracks greater than acceptable for exposure to a severe corrosive environment; ii) the element shall not become detached from its supports or fixings; SIST EN 1794-1:2011
EN 1794-1:2011 (E) 12 iii) the permanent deformation dhmax, in millimetres, after release of the load shall be less than A500L
iv) the deflections of structural elements shall not cause acoustic elements to become permanently displaced. A.3.3.3 Non-vertical noise reducing devices Load due to snow, self weight, etc. shall be considered as acting together with wind load. The acceptance criteria are as given in A.3.3.2 except that additionally the elastic vertical deflection dvmax, in millimetres, shall be less than A200L
A.3.4 Self supporting elements A.3.4.1 Acoustic elements which are not supported or kept in place by another structure shall meet all the criteria given in A.3.3.1 to A.3.3.3. A.3.4.2 Load bearing acoustic elements shall be designed to withstand all superimposed forces and meet the criteria specified in A.3.2 and A.3.3. A.4 Mechanical requirements for fixings of acoustical elements or structures A.4.1 Fixings for vertical noise reducing devices Fixings such as bolts, welds, adhesives, etc. shall withstand the force which they are designed to support multiplied by a factor S = 1,5 without symptoms of failure such as cracks or plastic deformation. A.4.2 Fixings for non-vertical noise reducing devices Load due to snow, self weight, etc. shall be considered as acting together with wind load. The acceptance criteria are as given in A.4.1 except that the load shall be multiplied by a factor S = 1,75. A.5 Noise absorbing cladding fixed to supporting walls A.5.1 Cladding on free standing walls in the open The mechanical requirements shall be as specified in A.3.2 and A.3.3 for free standing barriers under wind load and dynamic air pressure due to passing vehicles. A.5.2 Cladding shielded from wind load (in deep cuttings and tunnels) The mechanical requirements shall be as specified in A.3.2 and A.3.3 for free standing barriers, but only under dynamic air pressure load. A.6 Calculation and test reports A.6.1 Assessment of performance by calculation The calculation report shall include full details of assumptions and parameters used including: a) number and year of this European Standard, i.e. EN 1794-1:2011; SIST EN 1794-1:2011
EN 1794-1:2011 (E) 13 b) dimensions, including thickness of any reinforcement; c) materials used, together with their elastic moduli, elastic limits and other relevant data; d) theoretical basis of calculations; e) name of the product and the name and address of the manufacturer; f) name and address of the certifier of the calculation, with date and signature; g) cross sectional drawing with dimensions; h) results of calculations and assessment as to whether these indicate satisfactory performance for the specified load. A.6.2 Assessment of performance by testing A.6.2.1 General The load test shall be carried out on a representative panel which shall include an appropriate number of acoustic elements of the longest span for the element type, with posts or other supports similar to those used in practice. The supports shall be held in the horizontal plane and restrained from lateral movement and rotation. The supports may be propped if only the flexure of the acoustic elements is to be tested, otherwise the supports shall be fixed solely at their base, as in use. The test panel shall be allowed to reach equilibrium under laboratory conditions for at least 3 h before testing. Load tests shall be carried out at 20 °C. If the product is intended to be used at very low or very high temperatures, then the test may be repeated at - 20 °C and/or + 40 °C with appropriate conditioning time, if the material is regarded as being temperature sensitive. A.6.2.2 Test procedure The panel to be tested shall be supported as described in A.6.2.1. A 2 mm thick steel plate cut exactly to size
(± 10 mm) excluding the supporting frame shall be carefully placed onto the exposed area of the acoustic elements. The point at which the vertical deflection under this loading is greatest shall be determined and all measurements of deflection relative to a fixed datum level shall be taken at this point. An initial deflection reading shall be taken 30 min after placing the steel sheet. The steel sheet shall then be removed and the deflection reading repeated after 30 min. The difference between these two readings shall be described as the deflection under self weight. The steel sheet shall be replaced and an appropriate number of structural steel sections of the same length as the supports shall be uniformly distributed across the steel sheet parallel to the supports. The total weight of the structural sections including the steel sheet shall be equal to 1,5 times the total wind force (pressure x area) for which the panel is being tested. After 30 min under this loading, the deflection reading shall be repeated. The difference between this and the previous reading for loading by the steel sheet alone shall be described as the deflection under simulated wind load. The structural sections shall be carefully removed and after 30 min the deflection reading shall be repeated. The difference between this and the previous reading for loading by the steel sheet alone shall be described as the permanent deflection. A.6.2.3 Test report The test report shall include a full description of the test arrangements, including details of supports, procedures and loading of elements. It shall also include: a) number and year of this European Standard, i.e. EN 1794-1:2011; b) name and address of the testing institute with a dated signature of the person responsible; SIST EN 1794-1:2011
EN 1794-1:2011 (E) 14 c) exact identification of the tested element, the name and address of the manufacturer; d) full description of the materials and their thicknesses; e) weight of the element both wet and dry; f) drawing showing the cross section of the tested element; g) number of samples tested; h) results of tests and assessment as to whether these indicate satisfactory performance for the specified load. A.7 NOTE to Annex A – Shape factors for vertical and non-vertical noise reducing devices (informative) When applying shape factors to calculate wind loading to either the ends of a noise reducing device, or where there are discontinuities in the height of the noise reducing device, shape factors other than those in EN 1991-1-4 are recommended. To determine these wind shape factors, the noise reducing device will be divided in 4 zones according to EN 1991-1-4. The zones A, B and C are situated near to the ends of a noise reducing device; zone D is in the middle of the noise reducing device. The dimensions of the zones are indicated in the Figures A.1 and A.2 below. An emergency exit will be treated like a normal D area as long as the height of the door is not equal with the height of the noise reducing device.
Figure A.1 — Dimensions of the zones for a noise reducing device of constant height
SIST EN 1794-1:2011
EN 1794-1:2011 (E) 15
Key X mv Y hzone
Figure A.2 — Dimensions of the zones for a noise reducing device where there are differences in height along its length Figure A.1 indicates the dimensions of the zones for a noise reducing device of constant height. Figure A.2 indicates the dimensions of the zones for a noise reducing device where there are differences in height along its length. The recommended wind shape factors are given in the Table A.1 below. For barriers which have T shaped tops, 0,1 shall be added to the factors in Table A.1. For noise reducing devices at angles between 10° and 20° to the vertical, the additions should be determined by interpolation between 0,1 and 0,2. Table A.1 — Shape factor Cindex and additions for non vertical barriers
Cindex for vertical barriers Additions to Cindex for non vertical barriers Barrier zone
For . < 5° For 5° < . < 10° For . = 20° A 3,4 0,1 0,2 B 2,8 C 1,7 D 1,2 SIST EN 1794-1:2011
EN 1794-1:2011 (E) 16 Annex B (normative)
Self weight B.1 General The self weight of acoustical elements is used in two distinct ways.
The dry weight is needed to make an approximation of the noise insulation value of the element. Where elements can absorb water, the wet weight is an important consideration in the design of both elements and supporting structures. Limits on deflections are necessary to avoid acoustical leakage, diminution of the height or overloading of the supporting structure. Adequacy of mechanical performance in fulfilling the structural criteria given in this annex are demonstrated by ca
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.